1. Field of the Invention
The present invention generally relates to a wafer testing apparatus and wafer testing method, and more particularly relates to an auto-recovery wafer testing apparatus and wafer testing method.
2. Description of the Related Art
In today's society of information explosion, the market for the use of multimedia expends dramatically, which further induces the development of electronic devices moving towards digitalization, network accessibility, regional connection, and personalization. Responding to the demands, it is necessary for integrated circuits devices to meet the requirements of high-speed treatment, multi-functionality, integration, miniaturization and cost effectiveness. As a consequence, semiconductor manufacturing processes are becoming more miniaturized and with higher density. In semiconductor industry, IC manufacturing processes usually include three steps: wafer manufacturing, IC manufacturing, and IC packaging. The foregoing steps further require various wafer testing procedures to detect defective chips for ensuring high quality and yield.
Wafer testing can be divided basically into two portions, i.e., wafer probing and sorting during the manufacturing processes and final test following the packaging process. Wherein, wafer probing is performed after the finish of each manufacturing process, in which a testing apparatus (e.g., a wafer prober) is used to test chips on the wafer to classify the chips based on their individual electronic properties, so that the defective chips can be screened out from the subsequent manufacturing processes and thus manufacturing costs can be reduced.
In addition, a laser trimming procedure can be performed for chips that have spare circuits. First, the data obtained in the preceding processes are analyzed and characterized to sort out the data, such as the location of the chips and the layout of the circuits, that need repair. Next, a laser trimmer is used to perform a trimming process on the defective chips based on the repairable data. Thus, the foregoing testing steps of wafer probing, laser trimming and final test are critical steps for ensuring product quality and production efficiency as well as reducing manufacturing costs.
However, during the conventional processes of the foregoing wafer probing, laser trimming or final test step, interruptions may occur accidentally due to a breakdown of the testing apparatus (e.g., probing card and laser trimmer) or other unforeseeable causes. When that happens, the testing data for the chips that have been tested on a wafer will be lost upon the interruption of the system. Thus, when the problems causing the breakdown are solved or a new testing apparatus is used to continue the testing, the testing apparatus has to be set back to the initial position and the testing must be performed again on the chips at the initial position. Such repetitive testing processes due to data loss may cause damages on the chips through multiple testing processes, and the resetting of the testing apparatus will also lengthen the entire trimming process to cause the increase of the manufacturing cost and decrease of the production efficiency.